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H. FRANCART.

FURNACE, KlLN, OVEN, AND THE LIKE. APPLICATION FILED MAR. 26. I919.

1,314,486. Patented Aug. 26, 1919.

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H. FRANCART.

FURNACE, KILN, OVEN, AND THE LIKE.

APPLICATION FILED MAR. 26,1919.

Patented Aug. 26, 1919.

2 SHEETS-SHEET-Z.

Ill/MWTUB flein'z' fPa wcari THE CBLUMQIA PLAP'IOGHAP" CO" WASH'INDTON, D- C. I"

UNITE l HENRI FRANCART, OF HERNE HILL, LONDON, ENGLAND.

FURNACE, KILN, OVEN, AND THE LIKE.

Specification of Letters Patent.

Patented A11 26, 1919.

Application filed March 26, 1919. Serial No. 285,351.

T 0 all whom it may concern Be it known that I, HENRI FnANoAR'r, a subject of His Majesty the King of Belgium, and resident of Herne Hill, in the county of London, Kingdom of England, have invent-' ed certain new and useful Improvements in Furnaces, Kilns, Ovens, and the like, of which the following is a specification.

The present invention relates to industrial furnaces, kilns, ovens and the like, used for subjecting metals or other material or substance to heat-treatment such as is necessary in the manufacture of bricks, pottery, annealing, baking, firing or fusing articles. 1 In ovens of large size of the type wherein use'is made of direct heating by reversed flames, unequal heating is liable. to occur due on the one hand to the slowness with which theproducts of combustion pass down, over, or through the articles to be heat-treated, and on the other hand to the tendency of the flames to take the shortest path on their way to the device which sets up the draft.

The object of thepresent invention is to obviate this disadvantage'by setting up, independently of the draft, a powerful and continuous circulation of the products of combustion through or around the articles to be heat-treated in order that the said articles may be maintained at a substantially constant temperature throughout the whole Y period of treatment, thus insuring the carrying out of the heat-treatment-operation in a more efficient manner than in furnaces or ovens as heretofore constructed.

To this end the furnace within which combustion is effected is in open communication at its upper end withthe treatment-chamber so as to permit the passage of the products 4 of combustion from the former into the latter, as is always done in reversed-flame furnaces. In accordance with the presentinvention the lower part of the furnace is in similar communication with the lower part of the treatment-chamber so that the heat set up in the furnace by the combustion of the fuel therein causes a continuous circulation of the gases in a downward direction through the treatment-chamber, the circulation being maintained by reason of the difference in density of the streams. of gases within the two parts, the moving mixture moving upward by reason of its lower density and passing through the upper aperture in the dividing wall into the treatmentchamber, while the relatively cooler gases already in the treatment-chamber flow downward by reason of their greaterdensity and pass into the furnace through the lower aperture, the circulation being maintained in the same direction so long as the temperature within the furnace is in excess of the temperature within the treatmentc-hamber.

Preferably a fuel-gas is used as the combustible in the furnace. The effect of ad- 5 mitting and burning the fuel at the lower part of the furnace is to further accelerate the gaseous circulation because the com-- bustion of the gas, in addition to the thermodynamic efl'ect and with or without the ad- 7 mission of air into the furnace produces a suction-effect at the bottom of the combustion chamber which assists in drawing in the gases from the treatment-chamber into the lower part of the furnace. The effect of the circulation of the gaseous current is to convey the heat from the furnace to the materlal under treatment 1n the treatmentchamber, the gaseous current remaining at high temperature during the process of rapid circulation.

Tn carrying the invention into practice, a plurality of furnaces may be employed in combination with a. single treatmentchamher, or conversely a single furnace may be employed in combination with a plurality of treatment-chambers.

The invention is hereinafter described with reference to the accompanying drawings, which show diagrammatically a construction in accordance with the present invention, but I do not limit myself to the construction described and illustrated.

Figure 1 is a vertical section on the line A-B, Fig. 2 of a kiln in accordance with the present invention, and comprising a. plurality of furnaces connected in parallel' with a common treatment-chamber, such an arrangement illustrating the invention as it would be applied for the purpose of heating a tunnel-oven, the parts being shown in per spective for the sake of clearness.

Fig. 2 is a horizontal section.

Referring to the drawings, it will be seen that the kiln comprises a plurality of furnaces 3, 3 each consisting of a vertical cell containing an assemblage l of cellular-1y arranged or checker refractory brickwork serving as a heat accumulator. Each furnace is separated from the common treatmerit-chamber 5 by a common dividing wall 6, that part of said wall appertaining to each ture within the corresponding combustionj ing the amount of air furnace being provided at its upper part with a through passage? and at its lower part with a similar passage 8.

To prevent loss of heat by radiation or conduction, the furnace is inclosed by brickwork walls 9 coated with a layer of earth 1 0.

11' are passages which lead the gases used as the combustible from thennain fuel-conduit 12 to the individual furnaces 3, each passage 11 being provided with a fuel-controllingvalve 13 for regulating the temperachamber.

14 are passages serving to deliver all from the main air conduit 15 to each individual. furnace ,3, each passage 14 being provided with an air-controlling valve 16 for regulatfurnace.

17' is a conduit leading to achimney not shown; 18.is a traveling tablefor carryingthearticles to be treated into the'furnace; and 19' is a door for closing the chargingopening of the furnace.

Inpoperation, the gases pass upward through the furnace and downward through the treatment-chamber, the gases tending to keep in" continuous movement during the heating operation, thus preventingthe' formation of pockets in which the'temperature' may be'either above or'below the required temperature with consequent detriment. to

the-success of the heating operation.- The gases, while circulating as above set forth,

are also subjected to'a force-directedalong the longitudinal axis of the treatment chamber and set up by the draft of the chim- Qney. withthe result that they follow in effect a'helicoidal'path as shown clearly by the arrow 17 in Fig. 1.

If desired, the kiln as HbOVO'SGiG forth may" formpart-of a tunnel oven divided into three zones the first of :which is an initial heating zone, the second the maximum heating-zone, while the third may be a' coolin'g zone.

The air necessary tosupport combustion may" be drawn into the furnace by the draft delivered to each treatment chamber embodying side walls which extend upwardly for connection in' the top of the treatment chamber; said side walls being provided attheir top'and bottoms wlth pairs of openings, said side walls ,beingspaced from the outer shell, transverse walls disposed between the side w'all's'and outer shell and forming a plurality of sepa-' rate furnaces, each furnace having communlcatlon w th .a palr of upper andlower openings, means for supplying a gaseous fuel to" each. furnace,-and a stack communie eating with one end of the. treatment chamber.-

2. A furnace, kiln, oven andthe like, com prising an outer shell having a longitudinal treatment chamber embodying side walls 1,

which extend upwardly for; connection with the top of' the treatment chamber, said side walls being provided at their top andgb'ottom' with pairs of openings,said side walls'being spaced from the outer shell, transverse walls disposed between the side walls and outer.

shell and forming a plurality of separate furnaces, each furnace hav ngcoinmunlcation with-a pair of upper and lower open iugs,a filler of checker brickwork arranged wlthineach furnace;sa1d filler termlnatlng 1 at said openings to leave them unobstructed,

means to supply'a gaseous fuel to each. fur

nace, and a stack communicatingwith one I,

end. of the treatment chamber.

In testimony whereof I have signed my name.

Copies of this patent may be obtained for five-cents each, by addressing the Commissioner of meta;

' 7 Washington, D. G. V

hereunto HENRi FRANCART. 

